Re: is everybody running a 38mm offset on 20" rims?

we have 5 x 115 and it does matter a lot. like the above stated, the 5 x 114.3 can and will eventually snap your studs right off without hubcentric rings. as far as offset, it all depends on the size of the wheels you want. you can get away with pretty much anything in the +35 to +42 range

Re: is everybody running a 38mm offset on 20" rims?

"Offset is the distance from a wheel's mounting surface on the hub to the center-line of the wheel, in millimeters. Negative offset means the mounting surface is towards the inside of the wheel. With positive offset, this surface is biased towards the outside. Typically, wider tires require more positive offset to avoid contact on the inner fender well."

I have 20in by 8.5 with a +40mm offset...i have no rubbing on the inner fender at all...but i did have to roll my fenders front and rear, mine is as low as it can go with that size rim and tire (245/35ZR20)

Re: is everybody running a 38mm offset on 20" rims?

Originally Posted by txbest1980

we have 5 x 115 and it does matter a lot. like the above stated, the 5 x 114.3 can and will eventually snap your studs right off without hubcentric rings. as far as offset, it all depends on the size of the wheels you want. you can get away with pretty much anything in the +35 to +42 range

Very true about studs breaking, but then again, op will have three other wheels to support vehicle. lol

Real tire shops will refuse to work on your wheels/tires if they recognize that you have wrong wheels (vs bolt pattern).

Re: is everybody running a 38mm offset on 20" rims?

5x115 is the proper pattern, especially when getting into a 20" rim.
I'm puttin hub rings on my 20s just have to pick them up, they ordered the wrong ones 2 weeks ago.
I'm also running on 245/35/20 fit and ride perfect.

Re: is everybody running a 38mm offset on 20" rims?

There are alot more 5x114.3 wheels out there since that is and has been the Ford Mustang's bolt pattern. Only thing is that most of those wheels are musclecar-ish and not really flattering to a luxury sedan.

I've been over this many times on other forums in the argument "is it safe" etc. Naturally you are taking a small risk no matter what, but i've had 5x120 wheels on my LPE WS6 (5x120.65 stud pattern) for 5 years now. I've had the car up to 150mph, and run her through at least 8 SCCA sanctioned events with ZERO problems of any kind. I check my lugs every three months just out of good habit, and have never encountered a loose lug.

From an engineering standpoint, you are looking at a difference of less than 0.1mm per lug hole, and the deflection of aluminum at even 80lb/ft is more than 0.1mm. In english this means that your wheel lug holes will deform before the studs flex at all.

So it's certainly not as "safe" as the correct bolt pattern, but modern bridges have been built with looser tolerances and you drive over them every day and don't question it.